Car GPS tracker in the intelligent transportation space
There is no doubt that one of the most important enabling technologies in the intelligent vehicle space is the global positioning system (GPS). Without the ability accurately to determine a vehicle’s position on demand, there would be no way to cost-effectively implement autonomous or server-based vehicle navigation, nor would the ability to deliver customized, location-based services to the vehicle be possible. This chapter will provide a brief overview of the History of GPS.
Long before the development of the Car tracking GPS in use today, the concept of time transfer and positioning via signals from space was being researched around the world. These costly research projects were mainly sponsored by government agencies, to address their long-standing need to improve techniques for quickly and accurately positioning military vehicles and personnel on or above the battlefield. Troops and vehicles of centuries past relied on maps, charts, the stars and various electronic devices to find their location; however, with each improved method of determining position came inherent limitations. Boundaries and landmarks change with the passage of time, making mapping a continual, time-consuming task. Positioning via the stars has long been a necessity for mariners, but accurate time keeping and clear skies are at times elusive. Until the deployment of today’s GPS tracking device for cars, the ultimate solution did not exist – an ‘always on, always available’ system for determining an exact position anywhere on the globe.
The constellation of satellites being used for global positioning today has it roots in the satellite positioning and time transfer systems of the early 1960s. Like many successful endeavours, the GPS was conceived from building blocks of other programmes such as the Navy Navigation Satellite System (NNSS, or Transit), Timation and Project 621B. It is worthwhile to have a brief understanding of these predecessors of GPS in order fully to understand and appreciate the complexity of space-based radionavigation.
Transit was conceived to provide positioning capabilities for the US submarine fleet, and originally deployed in 1964. While Transit proved to be a tremendous success in demonstrating the concept of radio-navigation from space, the system was inherently inaccurate and required long periods of satellite observation in order to provide a user with enough information to calculate a position. Periods of observation in excess of 90 minutes were not uncommon, which limited the system’s effectiveness for positioning a submarine at sea, since extended surface time could leave the vessel vulnerable. Since all Transit satellites broadcast theirsignals at the same frequencies, the potential for interference allowed for only a small number of satellites. It was this limited number of satellites that necessitated the long perio ds of data collection, reducing the overall effectiveness of the system. This system was finally decommissioned in 1996.
The US Navy’s Timation satellite system, initially launched in 1967, was also in full swing by the early 1970s. Timation satellites carried payloads with atomic time standards used for time keeping and time transfer applications. This enabled a receiver to use the signal broadcast by each Timation satellite to measure the distance to that satellite by measuring the time it took the signal to reach the receiver. Timation provided a key proof of concept and a foundation building block for the GPS tracker, because without accurate time standards, the current GPS would not be possible. In 1973, building on the success and knowledge gained from Transit, Timation and Project 621B, and with inputs and support from multiple branches of the military, the US Department of Defense (DoD) launched the Joint Program for GPS. Thus, the NAVSTAR GPS project was born.
Long before the development of the Car tracking GPS in use today, the concept of time transfer and positioning via signals from space was being researched around the world. These costly research projects were mainly sponsored by government agencies, to address their long-standing need to improve techniques for quickly and accurately positioning military vehicles and personnel on or above the battlefield. Troops and vehicles of centuries past relied on maps, charts, the stars and various electronic devices to find their location; however, with each improved method of determining position came inherent limitations. Boundaries and landmarks change with the passage of time, making mapping a continual, time-consuming task. Positioning via the stars has long been a necessity for mariners, but accurate time keeping and clear skies are at times elusive. Until the deployment of today’s GPS tracking device for cars, the ultimate solution did not exist – an ‘always on, always available’ system for determining an exact position anywhere on the globe.
The constellation of satellites being used for global positioning today has it roots in the satellite positioning and time transfer systems of the early 1960s. Like many successful endeavours, the GPS was conceived from building blocks of other programmes such as the Navy Navigation Satellite System (NNSS, or Transit), Timation and Project 621B. It is worthwhile to have a brief understanding of these predecessors of GPS in order fully to understand and appreciate the complexity of space-based radionavigation.
Transit was conceived to provide positioning capabilities for the US submarine fleet, and originally deployed in 1964. While Transit proved to be a tremendous success in demonstrating the concept of radio-navigation from space, the system was inherently inaccurate and required long periods of satellite observation in order to provide a user with enough information to calculate a position. Periods of observation in excess of 90 minutes were not uncommon, which limited the system’s effectiveness for positioning a submarine at sea, since extended surface time could leave the vessel vulnerable. Since all Transit satellites broadcast theirsignals at the same frequencies, the potential for interference allowed for only a small number of satellites. It was this limited number of satellites that necessitated the long perio ds of data collection, reducing the overall effectiveness of the system. This system was finally decommissioned in 1996.
The US Navy’s Timation satellite system, initially launched in 1967, was also in full swing by the early 1970s. Timation satellites carried payloads with atomic time standards used for time keeping and time transfer applications. This enabled a receiver to use the signal broadcast by each Timation satellite to measure the distance to that satellite by measuring the time it took the signal to reach the receiver. Timation provided a key proof of concept and a foundation building block for the GPS tracker, because without accurate time standards, the current GPS would not be possible. In 1973, building on the success and knowledge gained from Transit, Timation and Project 621B, and with inputs and support from multiple branches of the military, the US Department of Defense (DoD) launched the Joint Program for GPS. Thus, the NAVSTAR GPS project was born.
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